Knob



FIG. 1 is a front view of a knob showing my new design;

FIG. 2 is a right side view thereof, the left side being a mirror image;

FIG. 3 is a bottom plan view thereof, the top plan being a mirror image; and,

FIG. 4 is a rear view thereof. 

The ornamental design for a knob, as shown and described. 